OFFSET
0,1
LINKS
Alonso del Arte, Table of n, a(n) for n = 0..999
Alex V. Kontorovich & Jeffrey C. Lagarias, Stochastic Models for the 3x+1 and 5x+1 Problems arXiv:0910.1944 [math.NT], 2009.
FORMULA
a(0) = 11; a(n) = 5a(n - 1) + 1 if a(n - 1) is odd, a(n) = a(n - 1)/2 otherwise.
EXAMPLE
11 is odd, so it's followed by 5 * 11 + 1 = 56.
56 is even, so it's followed by 56/2 = 28.
MATHEMATICA
NestList[If[EvenQ[#], #/2, 5# + 1] &, 5, 100]
PROG
(Magma) [n eq 1 select 11 else IsOdd(Self(n-1)) select 5*Self(n-1)+1 else Self(n-1) div 2: n in [1..80]]; // Vincenzo Librandi, Jul 04 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Alonso del Arte, Jun 21 2015
STATUS
approved